全文获取类型
收费全文 | 2298篇 |
免费 | 102篇 |
国内免费 | 182篇 |
专业分类
林业 | 219篇 |
农学 | 206篇 |
基础科学 | 73篇 |
136篇 | |
综合类 | 804篇 |
农作物 | 68篇 |
水产渔业 | 72篇 |
畜牧兽医 | 692篇 |
园艺 | 243篇 |
植物保护 | 69篇 |
出版年
2024年 | 12篇 |
2023年 | 36篇 |
2022年 | 91篇 |
2021年 | 88篇 |
2020年 | 78篇 |
2019年 | 109篇 |
2018年 | 46篇 |
2017年 | 116篇 |
2016年 | 120篇 |
2015年 | 91篇 |
2014年 | 155篇 |
2013年 | 150篇 |
2012年 | 166篇 |
2011年 | 203篇 |
2010年 | 119篇 |
2009年 | 124篇 |
2008年 | 101篇 |
2007年 | 146篇 |
2006年 | 91篇 |
2005年 | 84篇 |
2004年 | 83篇 |
2003年 | 60篇 |
2002年 | 58篇 |
2001年 | 56篇 |
2000年 | 49篇 |
1999年 | 24篇 |
1998年 | 27篇 |
1997年 | 20篇 |
1996年 | 15篇 |
1995年 | 13篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1985年 | 1篇 |
排序方式: 共有2582条查询结果,搜索用时 31 毫秒
111.
目的:观察芪参超微粉对雏鸡法氏囊疫苗免疫的影响。方法:将1日龄蛋公鸡360只随机均分为6组,21和35日龄,Ⅰ-Ⅴ组分别进行法氏囊疫苗首免和二免。14-21日龄,Ⅰ-Ⅲ组分别在基础日粮中添加1%、0.5%芪参超微粉和2%芪参散,Ⅳ组以玉屏风口服液饮水,V组为免疫对照组,Ⅵ组为不免疫空白对照组。试验前(14日龄,D0)及试验后第7(D7)、14(D14)、21(D21)、28(D28)、35(D35)、42(D42)天分别检测血清中IBD特异性抗体效价。试验后第7(D7)、21(D21)、35(D35)天检测外周血淋巴细胞增殖情况、血清中IL-2含量及体质量变化。结果:与免疫对照组相比,各用药组可以显著提高雏鸡法氏囊疫苗免疫效果,但各组间差异不显著。结论:芪参散经超微粉碎后使用较低剂量即可起到增强雏鸡免疫功能的作用。 相似文献
112.
28%苄嘧磺隆·二氯喹啉酸WP对水稻秧田杂草及产量的影响 总被引:1,自引:0,他引:1
研究了28%苄嘧磺隆·二氯喹啉酸对水稻秧田稗草[Echinochloa crusgalli (L.) Beauv.]、鸭舌草[Monochoia vaginalis(Burm.f.)]等的防除效果,并测定了杂草对氮、磷、钾和水分的影响以及对水稻产量的影响.结果表明,28%苄嘧磺隆·二氯喹啉酸WP对水稻秧田的主要杂草具有良好的防治效果,有效成分用量为168~420 g/hm2的28%苄嘧磺隆·二氯喹啉酸对水稻秧田稗草密度防效和鲜重防效分别为84.06%~98.50%、91.55%~98.63%,对鸭舌草的密度防效和鲜重防效分别为94.06%~100.00%、90.94%~100.00%,显著优于对照药剂10%苄嘧磺隆WP和50%二氯喹啉酸WP.28%苄嘧磺隆·二氯喹啉酸施用后,增产效果总体优于对照药剂,在水稻秧田具有良好的推广前景. 相似文献
113.
114.
115.
本研究旨在初步考察公英翘芦散对亚临床奶牛乳房炎的临床治疗效果。试验选取78头发病牛,其中38头牛为散发,用公英翘芦散治疗;40头牛集中对比治疗,随机分成2组,每组20头,分别用公英翘芦散和公英散进行治疗。用加州乳房炎检验(California mastitis trial,CMT)法检测公英翘芦散治疗后乳区患病状态并判定其治疗效果;用体细胞计数(somatic cell count,SCC)法检测公英翘芦散和公英散治疗后牛奶体细胞数并判定其治疗效果。结果显示,公英翘芦散给药7 d后,患病乳区由75个减少到28个,治疗效果非常显著,治愈率达到62.67%,有效率达到90.67%。与治疗前相比,公英翘芦散和公英散用药1 d后体细胞数均极显著降低(P<0.01),且公英翘芦散组SCC下降幅度明显超过公英散组。公英翘芦散组在给药2 d后体细胞数显著低于公英散组(P<0.05),给药3 d之后均极显著低于公英散组(P<0.01)。用药7 d后,公英翘芦散组治愈率可达68.29%,而公英散组治愈率只达到20.00%,差异极显著(P<0.01);公英翘芦散组有效率可达97.56%,而公英散组有效率为67.50%,差异极显著(P<0.01),说明公英翘芦散的治疗效果极显著优于公英散(P<0.01)。以上结果说明,公英翘芦散可以作为治疗亚临床奶牛乳房炎的有效药物,为奶牛乳房炎药物的开发提供参考。 相似文献
116.
117.
在注射兔病毒性出血症 (RHD)疫苗后 ,30只兔随机分为 2组 ,试验组兔饲喂含 1 5 %黄白散的饲料。从接种到第 1 80天 ,每组取兔 8只 ,每隔 1 5d采血 1次 ,检测血凝抑制 (HI)抗体 ;在接种前 1天及接种后 5、 1 0、 1 7、 2 4、 31、 41、 5 1d ,每组取兔 1 0只 ,采血检测ANAE+淋巴细胞百分率 ;在 1 80、 2 4 0、 30 0d时 ,每组分别取兔 5只做攻毒保护试验。结果表明 :2组兔HI抗体峰值分别为 7 3log2和 9 8log2 ,差异极显著 (P <0 0 1 ) ;试验组疫苗保护期可延长 60d ;试验组ANAE+率从第 1 0天至 5 1天与对照组比较 ,差异极显著(P<0 0 1 )。所以黄白散可增强兔接种RHD疫苗后的特异性免疫功能 ,增强RHD疫苗的免疫效果。 相似文献
118.
Walker MC Hill RC Guilford WG Scott KC Jones GL Buergelt CD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2001,15(5):463-466
A postprandial ammonia tolerance test (PPATT) was performed on normal dogs and dogs with signs that suggested they may have liver disease. All dogs underwent transcolonic scintigraphy, liver biopsy, or both and were assigned to extrahepatic disease, primary hepatocellular, and congenital portosystemic vascular anomalies (PSVA) groups. Each dog was fed a chicken and rice diet providing 25% of its estimated daily metabolizable energy requirement (MER) as an ammonia challenge. This is practical in patients with liver disease because ammonium chloride administration often causes vomiting or ammonia toxicity. Venous ammonia concentrations were measured before feeding and every 2 hours after feeding for 8 hours. No difference in mean ammonia concentrations between dogs with extrahepatic disease and control dogs was found. Therefore, the specificity of the PPATT was 100%. Dogs with hepatocellular disease showed no change in mean ammonia concentration at any time point, before or after feeding, but sensitivity was greatest when venous ammonia was measured 6 hours after feeding (sensitivity before feeding, 28%, and after feeding, 36%). Among dogs with congenital PSVA, mean ammonia concentrations were higher than the reference range at all time points before and after feeding, and peak mean ammonia concentration occurred 6 hours after feeding. In this group, the sensitivity of the PPATT was 81% before feeding and 91% 6 hours after feeding. This study demonstrates that the measurement of venous ammonia concentration is a useful test to detect congenital PSVA, and the sensitivity of the test may be improved by sampling 6 hours after feeding. The PPATT has poor sensitivity in detecting primary hepatocellular disease. 相似文献
119.
120.
AIM: To study the effects of intrathymic inoculation of liver specific antigen (LSA) on hepatocyte apoptosis after liver allotransplantation. METHODS: Orthotopic liver transplantation was used in this study. Group Ⅰ: syngenic control (Wistar-to-Wistar); Group Ⅱ: acute rejection (SD-to-Wistar); Group Ⅲ: thymus inoculation of SD rat LSA day 7 before transplantation. The observation of general situation and survival time, hepatocyte apoptosis and LAT expression in liver transplants were used to analyze immune state of animals in different groups. RESULTS: The general situation of group Ⅰ was very well after transplantation. Recipients of groupⅡ lost body weight progressively and all died within day 9 to day 13 post transplantation. As for group Ⅲ, the general situation of recipients was remarkably better than that in group Ⅱ. The positive cells of apoptosis in group Ⅲ detected by TUNEL were not significantly different from that in group Ⅰ, but was significantly lower than that in group Ⅱ. LAT was detected at any time in group Ⅱ with peak expression at day 5 and day 7 post transplantation. In contrast, LAT was not detected in any other groups. CONCLUSION: Intrathymic inoculation of LSA protects hepatocytes from apoptosis after liver allotransplantation. 相似文献